This invention is related to tonneau covers for enclosing the cargo area of a vehicle, and more particularly to a cover having a resilient "J" shaped extrusion stitched along a side edge of the cover, and a complementary, aluminum extruded lip mounted along the top edge of the cargo box which mates with a curved lip on the resilient fastener. The resilient lip is adapted to unwind like a clock spring to accommodate variations in the distance between the sidewalls of the cargo box as well as variations in flexibility of the cover material. This invention also relates to means for clamping the rail to the cargo box without drilling any special holes.
A tonneau cover is often mounted over the cargo box area of certain vehicles, such as pickup trucks and boats to protect the vehicle interior and contents. Such covers have several problems. For example, the cargo box sidewalls of commercially available pickup trucks frequently vary in width because of manufacturing tolerances. Thus, a cover adapted to accommodate a class of vehicles frequently will be loose on some vehicles and tighter on others because the means for connecting the cover to the sidewalls do not accommodate such dimensional variations.
Another problem is that the tonneau cover is usually formed of a flexible material that can be somewhat stretched. However, in cold weather, the material loses its flexibility and becomes stiff, and thus, hard to install and prone to tear. During warmer weather, the flexible material becomes very soft and flexible, and thus, difficult to tension.
Further, commercially available fastening devices for connecting a tonneau cover to a cargo box are difficult to attach, and in some cases require drilling several holes in the cargo box sidewall which detracts from the ultimate resale value of the vehicle, and in other cases, are relatively complicated and expensive to install.